In Toaru Kagaku no Railgun T Mikoto Misaka and her friends prepare for the Daihasei Festival, a seven-day sports competition between different Esper schools, which, of course, also include the Tokiwadai middle school. Misaka and all other students of Tokiwadai are highly motivated and ready to do their best in the upcoming competition. However, all the fun ends, when another dark secret of the Academy City of Science and Technology is uncovered.